Vibration can be an important consideration when designing, testing, and maintaining machinery. For example, significant levels of vibration can indicate poor design or an impeding failure of the machinery. The presence of unexpected frequency peaks in a vibrating structure may indicate nonlinear interactions among the natural frequencies of the subassemblies, which can cause premature failure of the machinery. In some applications, detecting an increase in vibration amplitude is a trigger for initiating equipment maintenance and/or service.
Vibration detection is often performed in the field by attaching one or more accelerometers or other vibration sensors to the rotating machinery or other vibrating structure. Vibration sensors produce output signals that can be used to determine the amplitude and frequency of vibration. It is known that contact between the vibration sensor and the vibrating structure can be improved by rigidly attaching vibration sensors (i.e., accelerometers) to the rotating machinery. In general, rigidly attaching the vibration sensor improves the transmission of vibrations from the vibrating structure to the sensor. However, such rigid attachment may not be possible or at least not practical with hand held vibration meters, which are preferred for the field use. Instead, a hand held vibration detector is typically kept by hand in contact with rotating machinery in the field to measure the vibrations.
FIG. 1 is a plan view of a conventional vibration meter 100. In operation, a wand 3 of the vibration meter 100 contacts a vibrating structure 5. The vibrations are transmitted through the wand 3 to an accelerometer 2 inside a housing 4. When subjected to vibrations, the accelerometer 2 produces an output signal to be routed to electronics within the unit 100 via wires 6. The unit 100 then determines vibration amplitude/frequency based on the signal coming from the accelerometer. The output (i.e., the amplitude and frequency of the vibration) can be displayed using display 7. However, such a conventional device is sensitive to the quality of contact between the device and the vibrating structure. Therefore, the accuracy of reading for the vibration sensor in a hand-held device remains a problem.